CN115549789B - Signal transmission system and measuring equipment based on optical fiber - Google Patents
Signal transmission system and measuring equipment based on optical fiber Download PDFInfo
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- CN115549789B CN115549789B CN202210968811.5A CN202210968811A CN115549789B CN 115549789 B CN115549789 B CN 115549789B CN 202210968811 A CN202210968811 A CN 202210968811A CN 115549789 B CN115549789 B CN 115549789B
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- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
Abstract
The embodiment of the application discloses a signal transmission system and measurement equipment based on optical fibers, and relates to the technical field of signal transmission. The signal transmission system comprises an input stage module, a signal splitting module, an optical fiber transmission module and a signal merging module which are connected in sequence; the signal splitting module is provided with a filtering unit, a low-frequency processing unit and a high-frequency processing unit, and the low-frequency unit and the high-frequency unit are respectively connected with the output end of the filtering unit; the high-frequency processing unit is also connected with a first reference signal; the signal combining module is provided with a low-frequency receiving unit, a high-frequency receiving unit and a combining unit, and the low-frequency receiving unit and the high-frequency receiving unit are both connected with the combining unit; the high frequency receiving unit is also connected with a second reference signal, and the first reference signal and the second reference signal are used for controlling the gain of the transmission system. The scheme effectively reduces the influence of the optical fiber modulation characteristic on signal transmission and reduces signal distortion.
Description
Technical Field
The embodiment of the application relates to the technical field of signal transmission, in particular to a signal transmission system and measuring equipment based on optical fibers.
Background
Along with the improvement of semiconductor technology, the switching speed of the MOS tube is higher and higher, the Vgs voltage is smaller and smaller, so that the amplitude and the frequency of the common-mode voltage are improved, and the differential-mode voltage is reduced. Therefore, a measurement system using high common mode rejection is required to measure a signal flowing through a semiconductor, and the measurement system is required to have a high bandwidth and low noise.
At present, an optical fiber isolation mode is adopted in the existing measurement system to isolate front and rear signals and transmit the signals through an optical fiber. In the transmission process, there are two modes of converting an electrical signal into an optical signal, one is direct modulation of a laser diode and the other is external modulation of laser.
However, in the direct modulation mode of the laser diode, the dc offset and gain of the transmitted signal may vary with temperature due to the characteristics of the laser diode; in the external modulation mode of the laser, the principle of the modulator is that the light intensity is affected by the adjustment of the phase, the adjustment is nonlinear, and the low-frequency modulation characteristic is poor. Therefore, when an analog signal is transmitted through an optical fiber, the analog signal is extremely susceptible to the modulation characteristics, resulting in distortion of the received signal.
Disclosure of Invention
The embodiment of the application provides a signal transmission system and measurement equipment based on optical fibers, which effectively reduce the influence of optical fiber modulation characteristics on signal transmission and reduce signal distortion.
In a first aspect, an embodiment of the present application provides an optical fiber-based signal transmission system, including an input stage module, a signal splitting module, an optical fiber transmission module, and a signal combining module.
The input stage module is used for accessing a signal to be transmitted and performing scaling adjustment on the signal to be transmitted.
The signal splitting module is connected with the input stage module and is provided with a filtering unit, a low-frequency processing unit and a high-frequency processing unit, and the low-frequency unit and the high-frequency unit are respectively connected with the output end of the filtering unit; the filtering unit is used for filtering high-frequency interference; the low-frequency processing unit is used for carrying out frequency modulation on the low-frequency component of the signal to be transmitted; the high frequency processing unit is used for adding a first reference signal to the high frequency component of the signal to be transmitted.
The optical fiber transmission module is connected with the signal splitting module and is used for transmitting the high-frequency component and the low-frequency component of the split signal to be transmitted.
The signal combining module is connected with the optical fiber transmission module and is provided with a low-frequency receiving unit, a high-frequency receiving unit and a combining unit, and the low-frequency receiving unit and the high-frequency receiving unit are both connected with the combining unit; the high-frequency receiving unit is also connected with a second reference signal, and the first reference signal and the second reference signal are used for controlling the gain of the transmission system; the low-frequency receiving unit is used for demodulating and recovering the low-frequency component, the high-frequency receiving unit is used for recovering the high-frequency component, and the merging unit is used for recovering the signal to be transmitted according to the recovered low-frequency component and the high-frequency component.
In a second aspect, embodiments of the present application provide a measurement device comprising an optical fiber-based signal transmission system as described in the above embodiments.
In this embodiment of the present application, before the signal is transmitted through the optical fiber transmission module, the signal is scaled and adjusted through the input stage module, so that the signal can be adapted to the voltage range of optical fiber transmission, the signal splitting module performs frequency modulation on the low-frequency component of the signal through the low-frequency processing unit and then transmits the signal, and the signal splitting module extracts the high-frequency component in the signal through the high-frequency processing unit and superimposes the first reference signal in the high-frequency component. After transmission, the signal merging module recovers the low-frequency component through the low-frequency receiving module, recovers the high-frequency component through the high-frequency receiving module, and is also connected with a second reference signal in the process of recovering the high-frequency component, and the gain of the transmission system can be controlled by adjusting the first reference signal and the second reference signal, so that the gain stability of the high-frequency signal is kept. Therefore, the low-frequency component transmitted by the signal transmission system has better linearity, the high-frequency component can keep stable gain, the temperature characteristic of the signal transmission system is more reliable, the gain and the offset voltage are irrelevant to the optical fiber transmission characteristic, and the occurrence of signal distortion is effectively reduced.
Drawings
FIG. 1 is a schematic block diagram of an optical fiber-based signal transmission system provided in an embodiment of the present application;
fig. 2 is a schematic structural diagram of an optical fiber-based signal transmission system according to an embodiment of the present application;
FIG. 3 is a schematic diagram of a filter passband provided in an embodiment of the present application;
fig. 4 is a schematic structural diagram of an input stage module according to an embodiment of the present application.
Detailed Description
The present application is described in further detail below with reference to the drawings and examples. It is to be understood that the embodiments described herein are for purposes of illustration and not limitation. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present application are shown in the drawings.
It should be noted that, in this document, relational terms such as first and second are used solely to distinguish one entity or action or object from another entity or action or object without necessarily requiring or implying any actual such relationship or order between such entities or actions or objects and without limitation to the number of such entities or actions or objects, which may be one or more. It is to be understood that the entities or operations or objects so used may be interchanged where appropriate, such that embodiments of the application may be capable of implementation in other ways than those illustrated or described herein.
Fig. 1 is a schematic block diagram of an optical fiber-based signal transmission system according to an embodiment of the present application, where the signal transmission system is based on optical fibers, such as an analog signal, for example. As shown in fig. 1, the optical fiber-based signal transmission system includes an input stage module 110, a signal splitting module 120, an optical fiber transmission module 130, and a signal combining module 140. The input stage module 110, the signal splitting module 120, the optical fiber transmission module 130 and the signal combining module 140 are sequentially connected.
The input stage module 110 is connected to the signal to be transmitted, and performs scaling adjustment on the signal to be transmitted, for example, adjusts the signal to be input through a variable gain amplifier, so that the signal to be input can be adapted to the voltage range of the optical fiber transmission. For example, for some signals with smaller voltage amplitudes, scaling can enable small signals to have better signal-to-noise ratios.
The signal splitting module 120 is used as a processing module before signal transmission, and splits the signal to be transmitted after scaling adjustment, for example, into a low-frequency component and a high-frequency component. The signal splitting module 120 includes a filtering unit, a low-frequency processing unit, and a high-frequency processing unit, where the low-frequency processing unit and the high-frequency processing unit are connected with an output end of the filtering unit, that is, signals to be transmitted after high-frequency interference is filtered by the filtering unit enter the low-frequency processing unit and the high-frequency processing unit respectively, so as to split into a low-frequency component and a high-frequency component, and the filtering unit can adopt a low-pass filter to filter the high-frequency interference. The low frequency processing unit selects a low frequency component in the signal to be transmitted and frequency modulates it. And the high-frequency processing unit selects the high-frequency component in the signal to be transmitted.
The low frequency component and the high frequency component in the signal to be transmitted are respectively transmitted through the optical fiber transmission module 130, and it is conceivable that the optical fiber transmission module 130 transmits the signal through an optical fiber, and the manner of converting the electrical signal into the optical signal can be direct modulation of a laser diode or external modulation of laser.
The signal combining module 140 is used as a processing module after signal transmission, and combines the transmitted low-frequency component and high-frequency component to recover the signal to be transmitted before transmission. The signal combining module 140 includes a low frequency receiving unit, a high frequency receiving unit, and a combining unit, and it is conceivable that the low frequency receiving unit and the high frequency receiving unit receive signals (such as a low frequency component and a high frequency component) transmitted in an optical fiber as a unit in which the signal combining module is connected to the optical fiber transmission module. The low-frequency receiving unit and the high-frequency receiving unit are both connected with the merging unit, and the low-frequency receiving unit is used for recovering low-frequency components, such as demodulating received signals to recover transmitted low-frequency components, and inputting the low-frequency components into the merging unit; the high frequency receiving unit is used for recovering the high frequency component and inputting the recovered high frequency component into the merging unit. The merging unit restores the signal to be transmitted according to the received low-frequency component and high-frequency component.
In addition, the high-frequency processing unit is also connected with a first reference signal, and the high-frequency receiving unit is also connected with a second reference signal. After the first reference signal is transmitted through the optical fiber module, the high-frequency receiving unit is recovered, and the high-frequency receiving unit can enable the voltage amplitude of the transmitted first reference signal to reach the voltage amplitude of the second reference signal, so that the effect of adjusting the gain of the transmission system can be achieved by adjusting the first reference signal and the second reference signal.
Before the signal is transmitted through the optical fiber transmission module 130, the signal is scaled and adjusted through the input stage module 110, the low-frequency processing unit in the signal splitting module 120 modulates the frequency of the low-frequency component of the signal, and then the signal is transmitted, the high-frequency processing unit extracts the high-frequency component in the signal, and the first reference signal is superimposed in the high-frequency component.
After transmission, the signal combining module 130 recovers the low-frequency component through the low-frequency receiving unit, recovers the high-frequency component through the high-frequency receiving unit, and accesses the second reference signal in the process of recovering the high-frequency component, and can realize the control of the gain of the transmission system by adjusting the first reference signal and the second reference signal, so as to keep the gain of the high-frequency signal stable.
Therefore, the low-frequency component transmitted by the signal transmission system has better linearity, the high-frequency component can keep stable gain, the temperature characteristic of the signal transmission system is more reliable, the gain and the offset voltage are irrelevant to the optical fiber transmission characteristic, and the occurrence of signal distortion is effectively reduced.
In some embodiments, the low frequency processing unit includes a first low pass filter, a first operational amplifier, a voltage controlled oscillator, and a first detection circuit. The first low-pass filter is used for selecting low-frequency components in the signal to be transmitted and inputting the low-frequency components into the non-inverting input end of the first operational amplifier, the output end of the first operational amplifier is connected with the voltage-controlled oscillator, and the output end of the voltage-controlled oscillator is connected with the first detection circuit and is connected with the inverting input end of the first operational amplifier through the first detection circuit. A feedback capacitor is also connected between the output of the first operational amplifier and the inverting input.
After the low-frequency component of the signal to be transmitted is amplified by the first operational amplifier, a part of the signal enters the control end of the voltage-controlled oscillator so that the voltage-controlled oscillator generates a modulation signal and feeds the modulation signal back to the first operational amplifier through the detection circuit; the other part of the signal returns to the inverting input terminal of the first operational amplifier through the feedback capacitor.
The optical fiber is transmitted through the optical fiber transmission module after being processed by the low-frequency processing unit, compared with the light intensity characteristic of the optical fiber, the frequency characteristic of the optical fiber is excellent, and the precision of a low-frequency signal can be ensured. Therefore, the low-frequency processing unit extracts the low-frequency component through the first low-pass filter, and frequency adjusts the low-frequency component through the voltage-controlled oscillator, the first detection circuit and the operational amplifier, so that the influence of the modulation characteristic (such as temperature influence gain, nonlinear modulation and the like) of the optical fiber on signal transmission is reduced, and the distortion of the signal is effectively reduced.
It should be noted that, each low-pass filter in the present application may also be a circuit formed by components such as a resistor, a capacitor, and the like, which plays a role in low-pass filtering; likewise, each high-pass filter can also be a circuit which is formed by adopting components such as a resistor, a capacitor and the like and has the function of high-pass filtering; the detection circuits can also be diode envelope detectors formed by connecting a capacitor and a resistor in parallel by adopting diode output terminals, or triode emitter envelope detectors.
In some embodiments, the high frequency processing unit includes a first high pass filter and a first adder. The first high-frequency filter extracts high-frequency components in the signal to be transmitted and inputs the high-frequency components to a first input end of the first adder. And the second input end of the first adder is connected to the first reference signal, and the frequency band of the first reference signal is located outside the passband of the first high-pass filter.
It will be appreciated that the high pass filter (or low pass filter) may allow signals of a frequency range to pass through, i.e., the passband of the high pass filter. Illustratively, the first reference signal is a sine wave signal with a frequency f1 determined by a voltage effective value; the passband of the first high-pass filter FL2 has the lowest frequency f2, and therefore, if the frequency band of the first reference signal is outside the passband of the first high-pass filter FL2, f1 is smaller than f2.
The signals (the high-frequency component and the first reference signal) processed by the high-frequency processing unit are not interfered with each other in the optical fiber transmission module, and the high-frequency signal and the first reference signal are transmitted by the optical fiber transmission module, so that the gain of the whole transmission system can be determined according to the first reference signal and the second reference signal accessed by the high-frequency receiving unit, and the gain of the transmission system can be controlled by adjusting the first reference signal and the second reference signal, thereby avoiding the influence of the change of the gain caused by the influence of the temperature of the optical fiber, realizing flexible control of the gain of the transmission system, and being beneficial to reducing the occurrence of the condition of signal distortion.
In some embodiments, the low frequency receiving unit includes a second detection circuit and a second low pass filter, an output end of the second detection circuit is connected to the second low pass filter, and an input end of the second detection circuit is connected to the optical fiber transmission module, for receiving the transmitted signal and recovering it. The low frequency receiving unit is used for receiving the low frequency component transmitted after frequency modulation, demodulation is realized through the second detection circuit and the second low-pass filter, so as to recover the low frequency component, and the recovered low frequency component is input into the merging unit.
In some embodiments, the high frequency receiving unit includes a first variable gain amplifier, a second high pass filter, and a gain feedback. The output end of the first variable gain amplifier is connected with the input end of the second high-pass filter, and the output end of the first variable gain amplifier is also connected with the input end of the gain feedback device. The output end of the gain feedback device is also connected with the control end of the first variable gain amplifier of the signal, and the output end of the gain feedback device is used for adjusting the voltage of the control end of the first variable gain amplifier.
It can be understood that the second reference signal is connected to the high frequency receiving unit through a gain feedback device, and the gain feedback device controls the control end of the first variable gain amplifier U4, so that the first variable gain amplifier U4 controls the signal scaling, for example, controls the first variable gain amplifier U4 to make the voltage amplitude of the output signal trend to the second reference signal, and the output signal is the first reference signal transmitted through the optical fiber transmission module.
Therefore, the high-frequency receiving unit realizes that the gain of the transmission system can be adjusted through the first reference signal and the second reference signal, ensures that the gain of the transmission system is stable and is not influenced by optical fiber transmission, thereby effectively reducing the uncontrollability of gain offset caused by the optical fiber modulation characteristic and reducing signal distortion.
In some embodiments, the gain feedback device includes a band pass filter, an RMS (Root Mean Square) detector, and a second operational amplifier.
The output end of the band-pass filter is connected with the input end of the RMS detector, the output end of the RMS detector is connected with the inverting input end of the second operational amplifier, the non-inverting input end of the second operational amplifier is connected with a second reference signal, and the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier through a feedback capacitor. In addition, the output end of the second operational amplifier is connected with the control end of the first variable gain amplifier.
It can be understood that the passband of the bandpass filter is adapted to the passband of the first reference signal, that is, the passband of the bandpass filter is also located outside the passband of the second highpass filter, so that the signal I corresponding to the passband of the first reference signal is extracted and input into the RMS detector to obtain the voltage amplitude of the signal I, and then the voltage amplitude of the signal I output by the first variable gain amplifier can reach the voltage amplitude of the second reference signal through feedback control of the second operational amplifier, thereby realizing adjustment of the gain of the transmission system.
In some embodiments, the combining unit includes a second adder, a third low-pass filter, and a first buffer. The second adder, the third low-pass filter and the first buffer are sequentially connected, the output end of the second adder is connected with the input end of the third low-pass filter, and the output end of the third low-pass filter is connected with the input end of the first buffer. Furthermore, the first input and the second input of the second adder are connected to the low frequency receiving terminal and the high frequency receiving unit, respectively.
It can be understood that the low-frequency component and the high-frequency component fused by the second adder are input into the third low-pass filter to filter out the out-of-band signal, and finally the first buffer is used for carrying out impedance transformation to realize the recovery of the signal to be transmitted.
Fig. 2 is a schematic structural diagram of an optical fiber-based signal transmission system according to an embodiment of the present application, where the signal transmission system accesses a signal to be transmitted through an input stage module 110, and performs scaling adjustment on the signal to adapt to a voltage range of transmission. The adjusted signal to be transmitted enters the filtering unit 121 of the signal splitting module 120, for example, enters the low-pass filter FL1, and the out-of-band noise is filtered by the low-pass filter FL 1. The signal is input to the first low-pass filter FL3 of the low-frequency processing unit 122, and the low-frequency component is extracted and input to the first operational amplifier U1.
The low frequency processing unit 122 realizes frequency modulation of the low frequency component by the first operational amplifier U1, the voltage controlled oscillator U2, and the first detection circuit. In the modulation of the low frequency component, the first operational amplifier U1 is employed to servo the detected signal so that the detected signal is equal to the input signal (low frequency component). The error source of the transmission of such low frequency components will depend on the difference between the first and second detection circuits and the frequency error of the optical fiber system, while the errors and non-linearities introduced by the voltage controlled oscillator U2 itself will be compensated by the first operational amplifier U1. The stability of each detection circuit is relatively easy to ensure, and the error of the optical fiber system in frequency is small and can be ignored, so that the accuracy of low-frequency component transmission is improved.
The signal filtered by the low-pass filter FL1 is also input to the first high-pass filter FL2 of the high-frequency processing unit 123, thereby extracting a high-frequency component, and the high-frequency component and the first reference signal Ref1 are superimposed by the first adder U3.
The low frequency component and the high frequency component are transmitted to the signal synthesizing module 140 through the optical fiber transmission module 120, respectively, and the low frequency receiving unit 141 demodulates and recovers the low frequency component through the second detection circuit and the second low pass filter FL7, and inputs into the second adder U6. The high frequency component is recovered by the high frequency receiving unit 142, wherein the high frequency receiving unit 142 extracts the first reference signal through the band pass filter FL4 in the gain feedback device 1421, then inputs the voltage value of the first reference signal into the second operational amplifier U5 through the RMS detector, and the second operational amplifier U5 is further connected to the second reference signal Ref2, so as to perform feedback control on the first variable gain amplifier U4, so that the gain of the transmission system is controlled, and finally extracts the high frequency component at the output end of the first variable gain amplifier U4 through the second high pass filter FL5 and inputs the high frequency component into the second adder U6.
The second adder U6 of the combining unit 143 inputs the superimposed low-frequency component and high-frequency component into the third low-pass filter FL6 to filter out the out-of-band signal, and finally performs impedance transformation through the first buffer U7 to recover the signal to be transmitted.
As shown in fig. 3, in which schematic diagrams of the pass bands of the respective filters are shown, the pass bands of the low-pass filter FL1 and the third low-pass filter FL6 coincide, the pass bands of the first high-pass filter FL2 and the second high-pass filter FL5 coincide, the pass bands of the first low-pass filter FL3 and the second low-pass filter FL7 coincide, and the pass band of the band-pass filter FL4 includes the frequency band of the first reference signal and is located outside the pass band of the first high-pass filter FL 2.
Therefore, before the signal is transmitted through the optical fiber transmission module, the signal is scaled and adjusted through the input stage module, so that the signal can be adapted to the voltage range of optical fiber transmission, the signal splitting module is adopted to carry out frequency modulation on the low-frequency component of the signal through the low-frequency processing unit and then transmit the signal, the signal splitting module is also used to extract the high-frequency component in the signal through the high-frequency processing unit, and the first reference signal is superposed in the high-frequency component. After transmission, the signal merging module recovers the low-frequency component through the low-frequency receiving unit, recovers the high-frequency component through the high-frequency receiving unit, and accesses the second reference signal in the process of recovering the high-frequency component, and can realize the control of the gain of the transmission system by adjusting the first reference signal and the second reference signal, so that the gain stability of the high-frequency signal is kept. Therefore, the low-frequency component transmitted by the signal transmission system has better linearity, the high-frequency component can keep stable gain, the temperature characteristic of the signal transmission system is more reliable, the gain and the offset voltage are irrelevant to the optical fiber transmission characteristic, and the occurrence of signal distortion is effectively reduced.
Fig. 4 is a schematic structural diagram of an input stage module according to an embodiment of the present application, where the input stage module includes a second buffer U8, a third buffer U9, a second variable gain amplifier U10, and two differential attenuators 111.
The input end of the second buffer U8 is connected with a signal to be transmitted through a first capacitor C1 and a first resistor R1 which are connected in parallel, and the input end of the second buffer U8 is also connected with a differential attenuator 111; the input end of the third buffer U9 is connected to the signal to be transmitted through a second capacitor C2 and a second resistor R2 which are connected in parallel, the input end of the third buffer U9 is also connected with another differential attenuator 111, and both differential attenuators 111 are grounded.
The output end of the second buffer U8 is connected to the first input end of the second variable gain amplifier U10, the output end of the third buffer U9 is connected to the second input end of the second variable gain amplifier U10, and in addition, the output end of the second variable gain amplifier U10 is connected to the filtering unit.
It can be appreciated that the differential attenuator 111 may attenuate an incoming signal to be transmitted, so as to eliminate the influence of harmonics on the signal, and the attenuated signal is input into the second variable gain amplifier U10 after being impedance-transformed by the buffers (the second buffer U8 and the third buffer U9), and scaling adjustment of the attenuated signal may be implemented by the second variable gain amplifier U10, so that the signal is in a voltage range adapted for optical fiber transmission.
It should be noted that, the differential attenuator 111 includes attenuation capacitors (e.g., C3 and C4) and attenuation resistors (e.g., R3 and R4) connected in parallel, and the attenuation capacitor and the attenuation resistor connected to the ground attenuate harmonics of the incoming signal to be transmitted, so as to reduce the influence of the harmonics on the signal to be transmitted.
In addition, the embodiment of the application also provides a measuring device, which comprises the optical fiber-based signal transmission system provided by the embodiment, and the measuring device can be an oscilloscope, an isolation probe and the like for measuring a semiconductor device, so that a measuring signal is not influenced by an optical fiber on the measuring device, and the accuracy of measurement is improved.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises an element.
Note that the above is only a preferred embodiment of the present application and the technical principle applied. Those skilled in the art will appreciate that the present application is not limited to the particular embodiments described herein, but is capable of numerous obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the present application. Therefore, while the present application has been described in connection with the above embodiments, the present application is not limited to the above embodiments, but may include many other equivalent embodiments without departing from the spirit of the present application, the scope of which is defined by the scope of the appended claims.
Claims (10)
1. An optical fiber-based signal transmission system, comprising:
the input stage module is used for accessing a signal to be transmitted and performing scaling adjustment on the signal to be transmitted;
the signal splitting module is connected with the input stage module and is provided with a filtering unit, a low-frequency processing unit and a high-frequency processing unit; the low-frequency processing unit and the high-frequency processing unit are respectively connected with the output end of the filtering unit; the filtering unit is used for filtering high-frequency interference; the low-frequency processing unit is used for carrying out frequency modulation on the low-frequency component of the signal to be transmitted; the high-frequency processing unit is used for adding a first reference signal to the high-frequency component of the signal to be transmitted;
the optical fiber transmission module is connected with the signal splitting module and is used for transmitting the high-frequency component and the low-frequency component of the split signal to be transmitted;
the signal combining module is connected with the optical fiber transmission module and is provided with a low-frequency receiving unit, a high-frequency receiving unit and a combining unit; the low-frequency receiving unit and the high-frequency receiving unit are both connected with the merging unit; the high-frequency receiving unit is also connected with a second reference signal, and the first reference signal and the second reference signal are used for controlling the gain of a transmission system; the low-frequency receiving unit is used for demodulating and recovering a low-frequency component, the high-frequency receiving unit is used for recovering a high-frequency component, and the merging unit is used for recovering the signal to be transmitted according to the recovered low-frequency component and the recovered high-frequency component.
2. The fiber-based signal transmission system of claim 1, wherein the low frequency processing unit comprises a first low pass filter, a first operational amplifier, a voltage controlled oscillator, and a first detection circuit;
the output end of the first low-pass filter is connected with the non-inverting input end of the first operational amplifier;
the output end of the first operational amplifier is connected with the control end of the voltage-controlled oscillator, and the output end of the first operational amplifier is also connected with the inverting input end of the first operational amplifier through a feedback capacitor;
the output end of the voltage-controlled oscillator is connected with the first detection circuit;
the first detection circuit is connected with the inverting input end of the first operational amplifier.
3. The optical fiber-based signal transmission system according to claim 1 or 2, wherein the high frequency processing unit comprises a first high pass filter and a first adder;
the output end of the first high-pass filter is connected with the first input end of the first adder;
the second input end of the first adder is connected to the first reference signal, and the frequency band of the first reference signal is located outside the passband of the first high-pass filter.
4. The optical fiber-based signal transmission system according to claim 1, wherein the low frequency receiving unit comprises a second detection circuit and a second low pass filter, and an output terminal of the second detection circuit is connected to the second low pass filter.
5. The optical fiber-based signal transmission system according to claim 1 or 4, wherein the high frequency receiving unit comprises a first variable gain amplifier, a second high pass filter, and a gain feedback device;
the input end of the second high-pass filter and the input end of the gain feedback device are both connected with the output end of the first variable gain amplifier;
the output end of the gain feedback device is connected with the control end of the first variable gain amplifier, and the gain feedback device is used for adjusting the voltage of the control end of the first variable gain amplifier.
6. The fiber-based signal transmission system of claim 5, wherein the gain feedback device comprises a bandpass filter, an RMS detector, and a second operational amplifier;
the output end of the band-pass filter is connected with the input end of the RMS detector;
the output end of the RMS detector is connected with the inverting input end of the operational amplifier;
the non-inverting input end of the second operational amplifier is connected with the second reference signal, the output end of the second operational amplifier is connected with the control end of the first variable gain amplifier, and the output end of the second operational amplifier is also connected with the inverting input end of the second operational amplifier through a feedback capacitor.
7. The fiber-based signal transmission system of claim 1, wherein the combining unit comprises a second adder, a third low-pass filter, and a first buffer; the output end of the second adder is connected with the input end of the third low-pass filter, and the output end of the third low-pass filter is connected with the input end of the first buffer.
8. The fiber-based signal transmission system of claim 1, wherein the input stage module comprises a second buffer, a third buffer, a second variable gain amplifier, and two differential attenuators;
the input end of the second buffer is connected with the signal to be transmitted through a first capacitor and a first resistor which are connected in parallel, the input end of the second buffer is connected with one differential attenuator, and the output end of the second buffer is connected with the first input end of the second variable gain amplifier;
the input end of the third buffer is connected with the signal to be transmitted through a second capacitor and a second resistor which are connected in parallel, the input end of the third buffer is connected with the other differential attenuator, and the output end of the third buffer is connected with the second input end of the second variable gain amplifier;
and both of the differential attenuators are grounded.
9. The fiber-based signal transmission system of claim 8, wherein the differential attenuator comprises an attenuation capacitor and an attenuation resistor connected in parallel.
10. A measurement device comprising an optical fiber based signal transmission system according to any one of claims 1-9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210968811.5A CN115549789B (en) | 2022-08-12 | 2022-08-12 | Signal transmission system and measuring equipment based on optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210968811.5A CN115549789B (en) | 2022-08-12 | 2022-08-12 | Signal transmission system and measuring equipment based on optical fiber |
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| Publication Number | Publication Date |
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| CN115549789A CN115549789A (en) | 2022-12-30 |
| CN115549789B true CN115549789B (en) | 2023-05-12 |
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| JPH0983270A (en) * | 1995-09-13 | 1997-03-28 | Nec Corp | Band split amplifier circuit |
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| WO2018119153A2 (en) * | 2016-12-21 | 2018-06-28 | Intel Corporation | Wireless communication technology, apparatuses, and methods |
| CN113472445A (en) * | 2021-06-25 | 2021-10-01 | 西北工业大学 | Dual-band RoF system based on PDM-DPMZM and adjusting method |
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| CA2946397C (en) * | 2014-04-21 | 2023-10-17 | Arris Enterprises Llc | Optical and rf techniques for aggregation of photo diode arrays |
| US10498448B2 (en) * | 2017-10-20 | 2019-12-03 | Arris Enterprises Llc | Stimulated Brillouin scattering (SBS) suppression in an optical communications system |
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| JPH0514264A (en) * | 1991-07-04 | 1993-01-22 | A T R Koudenpa Tsushin Kenkyusho:Kk | Light transmission system for radio link |
| JPH0983270A (en) * | 1995-09-13 | 1997-03-28 | Nec Corp | Band split amplifier circuit |
| US6252693B1 (en) * | 1999-05-20 | 2001-06-26 | Ortel Corporation | Apparatus and method for reducing impairments from nonlinear fiber effects in 1550 nanometer external modulation links |
| WO2018119153A2 (en) * | 2016-12-21 | 2018-06-28 | Intel Corporation | Wireless communication technology, apparatuses, and methods |
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